/// <summary>
 /// Instructs firebase to send data equal to the <see cref="value"/>. This must be preceded by an OrderBy query.
 /// </summary>
 /// <param name="child"> Current node. </param>
 /// <param name="value"> Value to start at. </param>
 /// <returns> The <see cref="FilterQuery"/>. </returns>
 public static FilterQuery EqualTo(this ParameterQuery child, string value)
 {
     return(child.EqualTo(() => value));
 }
 /// <summary>
 /// Instructs firebase to send data equal to null. This must be preceded by an OrderBy query.
 /// </summary>
 /// <param name="child"> Current node. </param>
 /// <returns> The <see cref="FilterQuery"/>. </returns>
 public static FilterQuery EqualTo(this ParameterQuery child)
 {
     return(child.EqualTo(() => null));
 }